A national committee says a referendum on Egypt's disputed constitution should be held on schedule, but told President Mohammed Morsi that he should drop some of the powers he has given himself.

The statement came after a presidential dialogue committee meeting that was boycotted by the main opposition leaders who had protested against the referendum. It did not suggest that Mr Morsi meet demands for the December 15 vote to be cancelled.

Opposition protesters are holding a sit-in outside the presidential palace in Cairo and are calling for more protests on Sunday.

Selim al-Awa, an Islamist at the meeting, said the committee found it would be a violation of earlier decisions to change the date of the referendum.

But the committee recommended removing articles that granted Mr Morsi powers to declare emergency laws and shield him from judicial oversight. Panel members said Mr Morsi had approved the recommendations.

The decision is unlikely to appease the opposition since it recommends the referendum go ahead as scheduled. Mr Morsi's initial declaration was to be rendered ineffective anyway after the constitution is approved.

Gamal Eid, a human rights lawyer, said the recommendations to rescind some powers were a "play on words" since Mr Morsi had already achieved the desired aim of finalising the draft constitution and protecting it over the past weeks from a judicial challenge.

Bassem Sabry, a writer and activist, said the changes to the declaration were a "stunt" that would embarrass the opposition but not resolve the problem. "In the end, Morsi got everything he wanted," he said.

"He protected the constituent assembly, the draft constitution and rammed into a referendum when people will have no time to study it against what he had promised before, which is that the document won't be put into a referendum without sufficient national consensus."

The majority of the 54 members of the committee were Islamists and members of the constitutional panel that drafted the disputed charter. But the main opponents were not present at the meeting, which lasted over 10 hours.